US3930822A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making carbon-containing glass resistors
Assignee: Corning Glass Works
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Filing: 1975-01-27
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Granted: 1976-01-06
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Expires: 1995-01-27
Abstract
Abstract An improved process for the production of carbon-containing glass resistors comprising impregnating porous glass with a furfuryl alcohol solution, flash-heating the impregnated glass at temperatures in the range of 150°-225°C. to polymerize the alcohol to a resin, and firing in a non-oxidizing atmosphere to convert the resin to carbon, is described. Substantially improved yields of high value resistors are obtained by the process.
Inventors
- 👤 Thomas H. Elmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:29
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/0652; H01B; H01B1/00; H01B1/14; H01B1/18
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
130 words
An improved process for making a carbon-impregnated glass electrical resistance material having an electrical resistivity in the 10 1 .5 - 10 10 ohm-centimeter range which comprises the steps of: a. impregnating a porous 96% silica glass with an aqueous solution of furfuryl alcohol wherein furfuryl alcohol is present in an amount ranging about 1-50 percent by volume; b. flash heating the solution impregnated porous 96% silica glass to a temperature in the range of about 150°-225°C. and maintaining it at a temperature in that range for a time at least sufficient to polymerize the furfuryl alcohol present in the glass to a resin; and c. firing the glass containing the resin in a non-oxidizing atmosphere to a temperature of at least about 1,200°C. to convert the resin to carbon.
Claim 2
Dependent Claim
130 words
An improved process for making a carbon-impregnated glass electrical resistance material having an electrical resistivity in the 10 1 .5 - 10 10 ohm-centimeter range which comprises the steps of: a. impregnating a porous 96% silica glass with an aqueous solution of furfuryl alcohol wherein furfuryl alcohol is present in an amount ranging about 1-50 percent by volume; b. flash heating the solution impregnated porous 96% silica glass to a temperature in the range of about 150°-225°C. and maintaining it at a temperature in that range for a time at least sufficient to polymerize the furfuryl alcohol present in the glass to a resin; and c. firing the glass containing the resin in a non-oxidizing atmosphere to a temperature of at least about 1,200°C. to convert the resin to carbon.
Claim 3
Dependent Claim
37 words
A process in accordance with claim 1 wherein flash-heating the solution-impregnated porous 96% silica glass comprises heating the glass at a rate of at least about 750°C. per hour to a temperature in the range of 150°-225°C.
Claim 4
Dependent Claim
54 words
A process in accordance with claim 2 wherein the aqueous solution of furfuryl alcohol comprises a stabilizing agent selected from the group consisting of the lower alkanols of from one to four carbon atoms per molecule, said stabilizing agent being present in an amount ranging from about 10-50 percent by volume of said solution.
Claim 5
Dependent Claim
13 words
A process in accordance with claim 3 wherein the stabilizing agent is ethanol.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |